From theinformation given,
total number of people = 291
Number of persons over 30 that prefer afternoon movies = 32
Number of persons that prefer afternoon movies = 70
This is a conditional probability.
Recall, Probability of event A given event B = P(A and B)/P(B)
Thus,
Probability that a person will be over 30 given that they prefer afternoon movies = 32/70
By multiplying by 100, it becomes
32/70 x 100
= 46%
Probability that a person will be over 30 given that they prefer afternoon movies = 46%